icblt.c

按照官方的说法：Cairo is a vector graphics library with cross-device output support. 翻译过来

	bits1 = 0;
	if (reverse)
	{
	    if (srcX < dstX)
		bits1 = *--src;
	    if (endmask)
	    {
		bits = FbScrRight(bits1, rightShift);
		if (FbScrRight(endmask, leftShift))
		{
		    bits1 = *--src;
		    bits |= FbScrLeft(bits1, leftShift);
		}
		--dst;
		*dst = FbDoMaskMergeRop (bits, *dst, mask & endmask);
		mask = FbPrev24Pix(mask);
	    }
	    while (n--)
	    {
		bits = FbScrRight(bits1, rightShift);
		bits1 = *--src;
		bits |= FbScrLeft(bits1, leftShift);
		--dst;
		*dst = FbDoMaskMergeRop(bits, *dst, mask);
		mask = FbPrev24Pix(mask);
	    }
	    if (startmask)
	    {
		bits = FbScrRight(bits1, rightShift);
		if (FbScrRight(startmask, leftShift))
		{
		    bits1 = *--src;
		    bits |= FbScrLeft(bits1, leftShift);
		}
		--dst;
		*dst = FbDoMaskMergeRop (bits, *dst, mask & startmask);
	    }
	}
	else
	{
	    if (srcX > dstX)
		bits1 = *src++;
	    if (startmask)
	    {
		bits = FbScrLeft(bits1, leftShift);
		bits1 = *src++;
		bits |= FbScrRight(bits1, rightShift);
		*dst = FbDoMaskMergeRop (bits, *dst, mask & startmask);
		dst++;
		mask = FbNext24Pix(mask);
	    }
	    while (n--)
	    {
		bits = FbScrLeft(bits1, leftShift);
		bits1 = *src++;
		bits |= FbScrRight(bits1, rightShift);
		*dst = FbDoMaskMergeRop(bits, *dst, mask);
		dst++;
		mask = FbNext24Pix(mask);
	    }
	    if (endmask)
	    {
		bits = FbScrLeft(bits1, leftShift);
		if (FbScrLeft(endmask, rightShift))
		{
		    bits1 = *src;
		    bits |= FbScrRight(bits1, rightShift);
		}
		*dst = FbDoMaskMergeRop (bits, *dst, mask & endmask);
	    }
	}
    }
#ifdef DEBUG_BLT24
    {
	int firstx, lastx, x;

	firstx = origX;
	if (firstx)
	    firstx--;
	lastx = origX + width/24 + 1;
	for (x = firstx; x <= lastx; x++)
	    ErrorF ("%06x ", getPixel (origDst, x));
	ErrorF ("\n");
	while (origNlw--)
	    ErrorF ("%08x ", *origLine++);
	ErrorF ("\n");
    }
#endif
}

void
fbBlt24 (FbBits	    *srcLine,
	 FbStride   srcStride,
	 int	    srcX,

	 FbBits	    *dstLine,
	 FbStride   dstStride,
	 int	    dstX,

	 int	    width,
	 int	    height,

	 int	    alu,
	 FbBits	    pm,

	 Bool	    reverse,
	 Bool	    upsidedown)
{
    if (upsidedown)
    {
	srcLine += (height-1) * srcStride;
	dstLine += (height-1) * dstStride;
	srcStride = -srcStride;
	dstStride = -dstStride;
    }
    while (height--)
    {
	fbBlt24Line (srcLine, srcX, dstLine, dstX, width, alu, pm, reverse);
	srcLine += srcStride;
	dstLine += dstStride;
    }
#ifdef DEBUG_BLT24
    ErrorF ("\n");
#endif
}
#endif /* FB_24BIT */

#if FB_SHIFT == FB_STIP_SHIFT + 1

/*
 * Could be generalized to FB_SHIFT > FB_STIP_SHIFT + 1 by
 * creating an ring of values stepped through for each line
 */

void
fbBltOdd (FbBits    *srcLine,
	  FbStride  srcStrideEven,
	  FbStride  srcStrideOdd,
	  int	    srcXEven,
	  int	    srcXOdd,

	  FbBits    *dstLine,
	  FbStride  dstStrideEven,
	  FbStride  dstStrideOdd,
	  int	    dstXEven,
	  int	    dstXOdd,

	  int	    width,
	  int	    height,

	  int	    alu,
	  FbBits    pm,
	  int	    bpp)
{
    FbBits  *src;
    int	    leftShiftEven, rightShiftEven;
    FbBits  startmaskEven, endmaskEven;
    int	    nmiddleEven;

    FbBits  *dst;
    int	    leftShiftOdd, rightShiftOdd;
    FbBits  startmaskOdd, endmaskOdd;
    int	    nmiddleOdd;

    int	    leftShift, rightShift;
    FbBits  startmask, endmask;
    int	    nmiddle;

    int	    srcX, dstX;

    FbBits  bits, bits1;
    int	    n;

    Bool    destInvarient;
    Bool    even;
    FbDeclareMergeRop ();

    FbInitializeMergeRop (alu, pm);
    destInvarient = FbDestInvarientMergeRop();

    srcLine += srcXEven >> FB_SHIFT;
    dstLine += dstXEven >> FB_SHIFT;
    srcXEven &= FB_MASK;
    dstXEven &= FB_MASK;
    srcXOdd &= FB_MASK;
    dstXOdd &= FB_MASK;

    FbMaskBits(dstXEven, width, startmaskEven, nmiddleEven, endmaskEven);
    FbMaskBits(dstXOdd, width, startmaskOdd, nmiddleOdd, endmaskOdd);

    even = TRUE;
    InitializeShifts(srcXEven, dstXEven, leftShiftEven, rightShiftEven);
    InitializeShifts(srcXOdd, dstXOdd, leftShiftOdd, rightShiftOdd);
    while (height--)
    {
	src = srcLine;
	dst = dstLine;
	if (even)
	{
	    srcX = srcXEven;
	    dstX = dstXEven;
	    startmask = startmaskEven;
	    endmask = endmaskEven;
	    nmiddle = nmiddleEven;
	    leftShift = leftShiftEven;
	    rightShift = rightShiftEven;
	    srcLine += srcStrideEven;
	    dstLine += dstStrideEven;
	    even = FALSE;
	}
	else
	{
	    srcX = srcXOdd;
	    dstX = dstXOdd;
	    startmask = startmaskOdd;
	    endmask = endmaskOdd;
	    nmiddle = nmiddleOdd;
	    leftShift = leftShiftOdd;
	    rightShift = rightShiftOdd;
	    srcLine += srcStrideOdd;
	    dstLine += dstStrideOdd;
	    even = TRUE;
	}
	if (srcX == dstX)
	{
	    if (startmask)
	    {
		bits = *src++;
		*dst = FbDoMaskMergeRop (bits, *dst, startmask);
		dst++;
	    }
	    n = nmiddle;
	    if (destInvarient)
	    {
		while (n--)
		{
		    bits = *src++;
		    *dst = FbDoDestInvarientMergeRop(bits);
		    dst++;
		}
	    }
	    else
	    {
		while (n--)
		{
		    bits = *src++;
		    *dst = FbDoMergeRop (bits, *dst);
		    dst++;
		}
	    }
	    if (endmask)
	    {
		bits = *src;
		*dst = FbDoMaskMergeRop(bits, *dst, endmask);
	    }
	}
	else
	{
	    bits = 0;
	    if (srcX > dstX)
		bits = *src++;
	    if (startmask)
	    {
		bits1 = FbScrLeft(bits, leftShift);
		bits = *src++;
		bits1 |= FbScrRight(bits, rightShift);
		*dst = FbDoMaskMergeRop (bits1, *dst, startmask);
		dst++;
	    }
	    n = nmiddle;
	    if (destInvarient)
	    {
		while (n--)
		{
		    bits1 = FbScrLeft(bits, leftShift);
		    bits = *src++;
		    bits1 |= FbScrRight(bits, rightShift);
		    *dst = FbDoDestInvarientMergeRop(bits1);
		    dst++;
		}
	    }
	    else
	    {
		while (n--)
		{
		    bits1 = FbScrLeft(bits, leftShift);
		    bits = *src++;
		    bits1 |= FbScrRight(bits, rightShift);
		    *dst = FbDoMergeRop(bits1, *dst);
		    dst++;
		}
	    }
	    if (endmask)
	    {
		bits1 = FbScrLeft(bits, leftShift);
		if (FbScrLeft(endmask, rightShift))
		{
		    bits = *src;
		    bits1 |= FbScrRight(bits, rightShift);
		}
		*dst = FbDoMaskMergeRop (bits1, *dst, endmask);
	    }
	}
    }
}

#ifdef FB_24BIT
void
fbBltOdd24 (FbBits	*srcLine,
	    FbStride	srcStrideEven,
	    FbStride	srcStrideOdd,
	    int		srcXEven,
	    int		srcXOdd,

	    FbBits	*dstLine,
	    FbStride	dstStrideEven,
	    FbStride	dstStrideOdd,
	    int		dstXEven,
	    int		dstXOdd,

	    int		width,
	    int		height,

	    int		alu,
	    FbBits	pm)
{
    Bool    even = TRUE;

    while (height--)
    {
	if (even)
	{
	    fbBlt24Line (srcLine, srcXEven, dstLine, dstXEven,
			 width, alu, pm, FALSE);
	    srcLine += srcStrideEven;
	    dstLine += dstStrideEven;
	    even = FALSE;
	}
	else
	{
	    fbBlt24Line (srcLine, srcXOdd, dstLine, dstXOdd,
			 width, alu, pm, FALSE);
	    srcLine += srcStrideOdd;
	    dstLine += dstStrideOdd;
	    even = TRUE;
	}
    }
#if 0
    fprintf (stderr, "\n");
#endif
}
#endif

#endif

#if FB_STIP_SHIFT != FB_SHIFT
void
fbSetBltOdd (FbStip	*stip,
	     FbStride	stipStride,
	     int	srcX,
	     FbBits	**bits,
	     FbStride	*strideEven,
	     FbStride	*strideOdd,
	     int	*srcXEven,
	     int	*srcXOdd)
{
    int	    srcAdjust;
    int	    strideAdjust;

    /*
     * bytes needed to align source
     */
    srcAdjust = (((int) stip) & (FB_MASK >> 3));
    /*
     * FbStip units needed to align stride
     */
    strideAdjust = stipStride & (FB_MASK >> FB_STIP_SHIFT);

    *bits = (FbBits *) ((char *) stip - srcAdjust);
    if (srcAdjust)
    {
	*strideEven = FbStipStrideToBitsStride (stipStride + 1);
	*strideOdd = FbStipStrideToBitsStride (stipStride);

	*srcXEven = srcX + (srcAdjust << 3);
	*srcXOdd = srcX + (srcAdjust << 3) - (strideAdjust << FB_STIP_SHIFT);
    }
    else
    {
	*strideEven = FbStipStrideToBitsStride (stipStride);
	*strideOdd = FbStipStrideToBitsStride (stipStride + 1);

	*srcXEven = srcX;
	*srcXOdd = srcX + (strideAdjust << FB_STIP_SHIFT);
    }
}
#endif

void
fbBltStip (FbStip   *src,
	   FbStride srcStride,	    /* in FbStip units, not FbBits units */
	   int	    srcX,

	   FbStip   *dst,
	   FbStride dstStride,	    /* in FbStip units, not FbBits units */
	   int	    dstX,

	   int	    width,
	   int	    height,

	   int	    alu,
	   FbBits   pm,
	   int	    bpp)
{
#if FB_STIP_SHIFT != FB_SHIFT
    if (FB_STIP_ODDSTRIDE(srcStride) || FB_STIP_ODDPTR(src) ||
	FB_STIP_ODDSTRIDE(dstStride) || FB_STIP_ODDPTR(dst))
    {
	FbStride    srcStrideEven, srcStrideOdd;
	FbStride    dstStrideEven, dstStrideOdd;
	int	    srcXEven, srcXOdd;
	int	    dstXEven, dstXOdd;
	FbBits	    *s, *d;
	int	    sx, dx;

	src += srcX >> FB_STIP_SHIFT;
	srcX &= FB_STIP_MASK;
	dst += dstX >> FB_STIP_SHIFT;
	dstX &= FB_STIP_MASK;

	fbSetBltOdd (src, srcStride, srcX,
		     &s,
		     &srcStrideEven, &srcStrideOdd,
		     &srcXEven, &srcXOdd);

	fbSetBltOdd (dst, dstStride, dstX,
		     &d,
		     &dstStrideEven, &dstStrideOdd,
		     &dstXEven, &dstXOdd);

#ifdef FB_24BIT
	if (bpp == 24 && !FbCheck24Pix (pm))
	{
	    fbBltOdd24  (s, srcStrideEven, srcStrideOdd,
			 srcXEven, srcXOdd,

			 d, dstStrideEven, dstStrideOdd,
			 dstXEven, dstXOdd,

			 width, height, alu, pm);
	}
	else
#endif
	{
	    fbBltOdd (s, srcStrideEven, srcStrideOdd,
		      srcXEven, srcXOdd,

		      d, dstStrideEven, dstStrideOdd,
		      dstXEven, dstXOdd,

		      width, height, alu, pm, bpp);
	}
    }
    else
#endif
    {
	fbBlt ((FbBits *) src, FbStipStrideToBitsStride (srcStride),
	       srcX,
	       (FbBits *) dst, FbStipStrideToBitsStride (dstStride),
	       dstX,
	       width, height,
	       alu, pm, bpp, FALSE, FALSE);
    }
}